# Dev utils as devDependencies

Production dependencies and dev dependencies should be installed as such so that production builds do not contain development dependencies. That being said, it can be difficult to dynamically require/import dependencies based on whether they have been installed or not.

Consider a Fela configuration relying on `fela-plugin-embedded` in all environments. Additionally, it uses `fela-beautifier` and `fela-plugin-validator` in development for debugging purposes, both installed as `devDependencies`. When trying to import or require them in production code, the application would throw a runtime error because they are not installed.

## With webpack

The main idea is to have 2 different files exporting plugins and enhancers (or any piece Fela configuration that differs between environments, really): one for development (`fela.development.js`), and one for production (`fela.production.js`).

The development one could look like this:

```js name=fela.development.js
import beautifier from 'fela-beautifier'
import validator from 'fela-plugin-validator'
import embedded from 'fela-plugin-embedded'

export const enhancers = [beautifier()]
export const plugins = [validator(), embedded()]
```

And the production one:

```js name=fela.production.js
import embedded from 'fela-plugin-embedded'

export const enhancers = []
export const plugins = [embedded()]
```

Then in Webpack, we provide the content of the correct file as a global variable (e.g. `FELA_CONFIG`) based on the environment:

```js name=webpack.config.js
const { resolve } = require('path')
const { ProvidePlugin } = require('webpack')

const NODE_ENV = process.env.NODE_ENV

module.exports = {
  plugins: [
    new ProvidePlugin({ FELA_CONFIG: resolve(`src/fela.${NODE_ENV}.js`) }),
  ],
}
```

Finally, when instantiating the Fela renderer, read the plugins and enhancers from the global `FELA_CONFIG` variable.

```js
/* global FELA_CONFIG */
export default createRenderer({
  plugins: FELA_CONFIG.plugins,
  enhancers: FELA_CONFIG.enhancers,
})
```

> This recipe relies on Webpack, but it should be applicable with any bundler able to expose a global variable.
